Height adjustment arrangement for chair headrest

ABSTRACT

A height adjustment arrangement for a headrest or the like includes a spring in a rear recess of a backrest. A T-shaped trigger member is received in the recess for biasing against the spring. A plate is secured onto the recess, with the plate having a slit. A finger tab of the trigger member projects from the horizontal slit. Two upright tubes are formed either on sides of a J-bar or on a backside of the backrest. An inverted U-shaped rod has a top attached to the headrest or the like and two groups of notches opposite the backrest. The trigger member is locked in two notches. In operation, the finger tab is pushed to compress the spring for disengaging the trigger member from the notches. The rod can be raised or lowered relative to the trigger member until a desired height is reached. Finally, the finger tab can be released to lock the trigger member in the other notches again.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to mechanisms for adjustablypositioning components of a chair relative to one another and moreparticularly to an improved height adjustment arrangement for a chairheadrest or the like.

[0003] 2. Description of Related Art

[0004] Well known chair backrest, arm, or seat height adjustmentmechanisms take various forms. Such prior mechanisms are typicallycomplex in constructions, trouble-prone, and unreliable in use.Moreover, protruding operating handles, levers or knobs of some priormechanisms are troublesome to manipulate, and are unsightly. Thus, theneed for improvement still exists.

SUMMARY OF THE INVENTION

[0005] It is an object of the present invention to provide a heightadjustment mechanism for headrest or the like. The mechanism comprises ahorizontal recess in a rear side of a backrest, the recess having acentral, cylindrical hole; resilient means anchored in the hole; asubstantially T-shaped trigger member inserted in the recess for biasingagainst the resilient means, the trigger member comprising a projectingfinger tab; a plate releasably secured onto the recess, the plate havinga central, horizontal slit with the finger tab projected therefrom; twoupright tubes formed on two opposite sides of a vertically stationaryupright backrest support which is attached to a backside of the backrestand an underside of a seat; and an inverted U-shaped rod having a topattached to the headrest or the like and two groups of a plurality ofnotches in a forward side facing the backrest, either group beingdisposed in either vertical section of the rod, the finger tab beingdisposed between the vertical sections of the rod, and two spacedportions in a horizontal section of the trigger member being fastened intwo flush ones of the notches in a non-operating position; wherein apushing of the finger tab compresses the resilient means until thespaced portions in the horizontal section of the trigger member clearfrom the flush ones of the notches, a raising or lowering of the rodwhile continuously pushing the finger tab moves the rod relative to thetrigger member until a predetermined height of the rod is reached andthe finger tab is flush with two other flush ones of the notches, and areleasing of the finger tab causes the trigger member to bounce rearwardfor fastening the spaced portions in the horizontal section of thetrigger member in the other flush ones of the notches again.

[0006] It is another object of the present invention to provide a heightadjustment mechanism for headrest or the like. The mechanism comprises ahorizontal recess in a rear side of a backrest, the recess having acentral, cylindrical hole; resilient means anchored in the hole; asubstantially T-shaped trigger member inserted in the recess for biasingagainst the resilient means, the trigger member comprising a projectingfinger tab; a plate releasably secured onto the recess, the plate havinga central, horizontal slit with the finger tab projected therefrom; twoupright tubes formed on a backside of the backrest below the recess witha vertically stationary upright backrest support disposed between thetubes, the vertically stationary upright backrest support having one endsecured to the backside of the backrest and the other end attached to anunderside of a seat; and an inverted U-shaped rod having a top attachedto the headrest or the like and two groups of a plurality of notches ina forward side facing the backrest, either group being disposed ineither vertical section of the rod, the finger tab being disposedbetween the vertical sections of the rod, and two spaced portions in ahorizontal section of the trigger member being fastened in two flushones of the notches in a non-operating position; wherein a pushing ofthe finger tab compresses the resilient means until the spaced portionsin the horizontal section of the trigger member clear from the flushones of the notches, a raising or lowering of the rod while continuouslypushing the finger tab moves the rod relative to the trigger memberuntil a predetermined height of the rod is reached and the finger tab isflush with two other flush ones of the notches, and a releasing of thefinger tab causes the trigger member to bounce rearward for fasteningthe spaced portions in the horizontal section of the trigger member inthe other flush ones of the notches again.

[0007] The above and other objects, features and advantages of thepresent invention will become apparent from the following detaileddescription taken with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is an exploded view of a first preferred embodiment ofarrangement for carrying out a height adjustment of chair headrest orthe like according to the invention;

[0009]FIG. 2 is an exploded view of a second preferred embodiment ofarrangement for carrying out a height adjustment of chair headrest orthe like according to the invention;

[0010]FIG. 3 is a perspective view of a chair having the first preferredembodiment of arrangement;

[0011]FIG. 4 is a sectional view of the arrangement of FIG. 1 mounted ina rear side of the backrest where a rod is locked;

[0012]FIG. 5 is a view similar to FIG. 4 where the rod is unlocked forbeing adapted to lower;

[0013]FIG. 6 is a perspective view of a chair having the first or secondpreferred embodiment of arrangement with a hanger mounted on top of therod in one configuration according to the invention; and

[0014]FIG. 7 is a view similar to FIG. 6 where a headrest is mounted ontop of the rod in another configuration according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Referring to FIGS. 1 to 4, a chair incorporates an arrangementfor adjusting height of a headrest or the like in accordance with theinvention. The arrangement comprises a horizontal recess 11 in a rearside of a backrest 1, a spring 2 anchored in a central, cylindrical holeof the recess 11, a substantially T-shaped trigger member 3 inserted inthe recess 11 for biasing against the spring 2, a rectangular plate 4threadedly secured onto the recess 11 by means of two fasteners (e.g.,screws) 8, the plate 4 having a central, horizontal slit 41 with afinger tab 31 of the trigger member 3 projected therefrom, and eithertwo upright tubes 51 formed on two opposite sides of a verticallystationary upright backrest support (or J-bar) 5 (as in a firstpreferred embodiment of FIG. 1) or two upright tubes 12 formed on thebackside of the backrest 1 below the recess 11 a predetermined distance(as in a second preferred embodiment of FIG. 2). The J-bar 5 has anupper end threadedly secured to the backside of the backrest 1 by meansof a plurality of fasteners (e.g., screws) 8 and a lower end attached tothe underside of a seat 7. The arrangement further comprises an invertedU-shaped rod 6 having two groups of a plurality of notches 61 in aforward side facing the backrest 1, either group being disposed in oneof two vertical sections of the rod 6 and each notch 61 having an upper,horizontal end as a stop and a lower, inclined surface for facilitatinga longitudinal motion of the backrest 1 relative to the rod 6. Thefinger tab 31 is disposed between the vertical sections of the rod 6 andtwo spaced portions in a horizontal section of the trigger member 3 arefastened in two flush notches 61.

[0016] Referring to FIG. 5 in conjunction with FIG. 4, a heightadjustment of the rod 6 relative to the backrest 1 by operating thearrangement will be described below. In a non-operating position asshown in FIG. 4, the spring 2 is fully expanded to push the triggermember 3 outward so as to fasten two spaced portions in the horizontalsection of the trigger member 3 in two flush notches 61. At thisposition, the trigger member 3 is locked, i.e., the trigger member 3 isstopped by the upper, horizontal ends of the notches 61. For eitherraising or lowering the rod 6 relative to the backrest 1 (see FIG. 5), auser has to push the finger tab 31 for sliding the finger tab 31 apredetermined distance and compressing the spring 2 until the spacedportions in the horizontal section of the trigger member 3 clear fromthe flush notches 61 for ensuring that there is no interference by thetrigger member 3 in a next downward movement of the rod 6. The user thenpushes the rod 6 down by one hand while continuously pushing the fingertab 31 by the other hand until a desired height is reached and thefinger tab 31 is flush with two other notches 61. Immediately, the usercan release the finger tab 31 to cause the trigger member 3 to bouncerearward for fastening two spaced portions in the horizontal section ofthe trigger member 3 in the flush notches 61 again.

[0017] Referring to FIGS. 6 and 7, in other embodiments a hanger 9 (seeFIG. 6) or a headrest 10 (see FIG. 7) is mounted on top of the rod 6 sothat a user can adjust height of the hanger 9 or the headrest 10relative to the backrest 1 for achieving the purpose of personal comfortor the like.

[0018] While the invention herein disclosed has been described by meansof specific embodiments, numerous modifications and variations could bemade thereto by those skilled in the art without departing from thescope and spirit of the invention set forth in the claims.

1. A height adjustment mechanism mounted in a chair, comprising: ahorizontal recess in a rear side of a backrest, the recess having acentral, cylindrical hole; a resilient element anchored in the hole; asubstantially T-shaped trigger member inserted in the recess for biasingagainst the resilient element, the trigger member comprising ahorizontal section having a projecting finger tab located between twospaced portions; a plate releasably secured onto the recess, the platehaving a central, horizontal slit, with the finger tab and the twospaced portions of the trigger member projecting through the horizontalslit; two upright tubes on opposite sides of a vertically stationaryupright backrest support which is attached to a backside of the backrestand an underside of a seat, with the two upright tubes being below therecess; an inverted U-shaped rod having two vertical rods, with eachvertical rod including a plurality of notches in a forward side facingthe backrest, the finger tab being disposed between the verticalsections of the rod, and with the two spaced portions in the horizontalsection of the trigger member being simultaneously received in twonotches in a non-operating position; and a predetermined member mountedon a top of the rod, wherein pushing of the finger tab moves theT-shaped trigger member into the recess towards the backrest andcompresses the resilient element until the spaced portions in thehorizontal section of the trigger member clear from the notches, raisingor lowering of the rod while continuously pushing the finger tab movesthe rod relative to the trigger member until a desirable height of therod is reached and the finger tab is aligned with two other notches, andreleasing of the finger tab causes the trigger member to bounce rearwardfor moving the spaced portions in the horizontal section of the triggermember in the two other notches for fastening the inverted U-shaped rodto the backrest again.
 2. The height adjustment mechanism of claim 1,wherein each of the notches has an upper, horizontal end and a lower,inclined surface.
 3. The height adjustment mechanism of claim 1, whereinthe predetermined member is a headrest.
 4. The height adjustmentmechanism of claim 1, wherein the predetermined member is a hanger.
 5. Aheight adjustment mechanism mounted in a chair, comprising: a horizontalrecess in a rear side of a backrest, the recess having a central,cylindrical hole; a resilient element anchored in the hole; asubstantially T-shaped trigger member inserted in the recess for biasingagainst the resilient element, the trigger member comprising aprojecting finger tab; a plate releasably secured onto the recess, theplate having a central, horizontal slit with the finger tab projectingfrom the central, horizontal slit; two upright tubes formed on abackside of the backrest below the recess with a vertically stationaryupright backrest support disposed between the tubes, the verticallystationary upright backrest support having one end secured to thebackside of the backrest and the other end attached to an underside of aseat; an inverted U-shaped rod having two vertical rods, with eachvertical rod including a plurality of notches in a forward side facingthe backrest, the finger tab being disposed between the verticalsections of the rod, and with the two spaced portions in the horizontalsection of the trigger member being simultaneously received in twonotches in a non-operating position; and a predetermined member mountedon a top of the rod, wherein pushing of the finger tab compresses theresilient means until the spaced portions in the horizontal section ofthe trigger member clear from the notches, raising or lowering of therod while continuously pushing the finger tab moves the rod relative tothe trigger member until a desired height of the rod is reached and thefinger tab is aligned with two other notches, and releasing of thefinger tab causes the trigger member to bounce rearward for moving thespaced portions in the horizontal section of the trigger member in theother two notches for fastening the inverted U-shaped rod to thebackrest again.
 6. The height adjustment mechanism of claim 5, whereineach of the notches has an upper, horizontal end and a lower, inclinedsurface.
 7. The height adjustment mechanism of claim 5, wherein thepredetermined member is a headrest.
 8. The height adjustment mechanismof claim 5, wherein the predetermined member is a hanger.
 9. The heightadjustment mechanism of claim 5, wherein the horizontal section of thetrigger member has a length beyond each of the two spaced portions andgreater than the central, horizontal slit for abutting with the plate onopposite sides of the horizontal slit when biased by the resilientmember and the finger tab is not pushed.
 10. The height adjustmentmechanism of claim 9 with the resilient element being a coil springaligned with projecting finger tab.
 11. The height adjustment mechanismof claim 10 with the plate removably secured onto the recess by threadedfasteners.
 12. The height adjustment mechanism of claim 11 with theplate closing the recess to define a chamber receiving the resilientelement and the trigger member.
 13. The height adjustment mechanism ofclaim 5 with the resilient element being a coil spring aligned withprojecting finger tab.
 14. The height adjustment mechanism of claim 5with the plate removably secured onto the recess by threaded fasteners.15. The height adjustment mechanism of claim 5 with the plate closingthe recess to define a chamber receiving the resilient element and thetrigger member.
 16. The height adjustment mechanism of claim 1, whereinthe horizontal section of the trigger member has a length beyond each ofthe two spaced portions and greater than the central, horizontal slitfor abutting with the plate on opposite sides of the horizontal slitwhen biased by the resilient member and the finger tab is not pushed.17. The height adjustment mechanism of claim 1 with the resilientelement being a coil spring aligned with projecting finger tab.
 18. Theheight adjustment mechanism of claim 1 with the plate removably securedonto the recess by threaded fasteners.
 19. The height adjustmentmechanism of claim 18 with the plate closing the recess to define achamber receiving the resilient element and the trigger member.
 20. Theheight adjustment mechanism of claim 1 with the plate closing the recessto define a chamber receiving the resilient element and the triggermember.